NURSERY PRACTICE ON THE NATIONAL FORESTS. 73 
safeguards are necessary to prevent losses resulting from unusual 
conditions. 
In cases where the slope of the ground permits and where a supply 
of water is available, heavy flooding of the beds will prevent frost 
damage. The temperature of the water is usually above that of the 
air and it does not cool so rapidly. A considerable quantity of wild 
meadow hay spread over the beds will prevent frost injury as well 
as rapid thawing in case freezing has already taken place. The 
method followed in orchards of building a smudge may be used. 
Either wood or hay will serve the purpose, and small piles will have 
to be distributed in the paths throughout the nursery. Emphasis 
must be laid upon the need of anticipating the danger, of preparing 
for it, and taking action when the danger is most imminent. Heavy 
frosts can generally be foreseen the evening before and the local 
Weather Bureau can doubtless notify the man in charge when there 
is any real danger. Thermostat alarms may also be provided. If 
proper precautions are taken, wholesale losses can be prevented even 
though the plants are tender and the frost heavy. Losses from frost 
have not in general been heavy at Forest Service nurseries. At the 
Savenac Nursery 1-0 western yellow pine, Douglas fir, and Engel- 
mann spruce ; at the Monument, Douglas fir and Engelmann spruce ; 
at the Pocatello, 1-0 western yellow pine not under shade frames; 
at the Wasatch, 2-0 Douglas fir ; and at the Boulder, 1-0 Douglas fir 
have been injured to some extent; while at the Wind Eiver spring- 
sown seedlings of noble fir were badly injured by a late frost. At the 
Beaver Creek Nursery mulching with ripe timothy hay effectually 
prevented frost damage, but resulted in the production of a heavy 
crop of hay, which vastly increased the amount of weeding neces- 
sary in the nursery. 
INSECTS. 
The principal insect damage which has been noted in the nurseries 
of the National Forests thus far has been due to cutworms, white 
grubs, grasshoppers, aphids, and pine-tip moths. The following 
information regarding life histories and habits of these insects and 
the general methods of combating them has been furnished by the 
Bureau of Entomology, which investigates insects affecting forest 
and shade trees and hardy shrubs, including forest nurseries. 
CUTWORMS. 1 
Cutworms are the larvae or caterpillars of night-flying moths and 
sometimes are destructive to young seedlings, cutting them off at or 
1 For further information on cutworms and their control, see U. S. Dept Agr Farmers' 
Bulletin 739. 
